Neurochemical Research

, Volume 41, Issue 3, pp 593–599 | Cite as

The Split Personality of Glutamate Transporters: A Chloride Channel and a Transporter

Original Paper


Transporters and ion channels are conventionally categorised into distinct classes of membrane proteins. However, some membrane proteins have a split personality and can function as both transporters and ion channels. The excitatory amino acid transporters (EAATs) in particular, function as both glutamate transporters and chloride (Cl) channels. The EAATs couple the transport of glutamate to the co-transport of three Na+ ions and one H+ ion into the cell, and the counter-transport of one K+ ion out of the cell. The EAAT Cl channel is activated by the binding of glutamate and Na+, but is thermodynamically uncoupled from glutamate transport and involves molecular determinants distinct from those responsible for glutamate transport. Several crystal structures of an EAAT archaeal homologue, GltPh, at different stages of the transport cycle, alongside numerous functional studies and molecular dynamics simulations, have provided extensive insights into the mechanism of substrate transport via these transporters. However, the molecular determinants involved in Cl permeation, and the mechanism by which this channel is activated are not entirely understood. Here we will discuss what is currently known about the molecular determinants involved in EAAT-mediated Cl permeation and the mechanisms that underlie their split personality.


Glutamate transport EAAT SLC1 Anion conductance GltPh 



R.J.C. is supported by an Australian Postgraduate Award and a John Lamberton scholarship. This work is supported by a National Health and Medical Research Council Project Grant (#1048784) to R.M.R. and R.J.V.


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Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  1. 1.Discipline of Pharmacology, School of Medical Sciences and Bosch InstituteUniversity of SydneySydneyAustralia

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